如何在java中制作倒数计时器

我是编程的初学者（学生）并被指派创建一个游戏。 我正在制作的游戏叫做boggle。 其中玩家必须在给定时间内在随机字母板中找到单词。 但是我在创建计时器时遇到了麻烦。 这是我的计时器应该做的：

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• 动态输入的时间（设定时间）
• 从输入时间倒计时到0
• 当o =>跳出循环时

我需要知道的是如何使其倒计时。 我不认为我需要一个ActionListener，因为它在创建类的那一刻开始滴答作响。

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任何帮助，建议，链接，向正确的方向推进都将张开双臂接受。

Answer 1

import java.util.Scanner; import java.util.Timer; import java.util.TimerTask; public class Stopwatch { static int interval; static Timer timer; public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.print("Input seconds => : "); String secs = sc.nextLine(); int delay = 1000; int period = 1000; timer = new Timer(); interval = Integer.parseInt(secs); System.out.println(secs); timer.scheduleAtFixedRate(new TimerTask() { public void run() { System.out.println(setInterval()); } }, delay, period); } private static final int setInterval() { if (interval == 1) timer.cancel(); return --interval; } } 

尝试这个。

Answer 2

您会看到有人使用Timer类来执行此操作。 不幸的是，它并不总是准确的。 最好的办法是在用户输入输入时获取系统时间，计算目标系统时间，并检查系统时间是否超过目标系统时间。 如果有，则打破循环。

Answer 3

您可以使用applet创建倒数计时器，下面是代码，

  import java.applet.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.Timer; // not java.util.Timer import java.text.NumberFormat; import java.net.*; /** * An applet that counts down from a specified time. When it reaches 00:00, * it optionally plays a sound and optionally moves the browser to a new page. * Place the mouse over the applet to pause the count; move it off to resume. * This class demonstrates most applet methods and features. **/ public class Countdown extends JApplet implements ActionListener, MouseListener { long remaining; // How many milliseconds remain in the countdown. long lastUpdate; // When count was last updated JLabel label; // Displays the count Timer timer; // Updates the count every second NumberFormat format; // Format minutes:seconds with leading zeros Image image; // Image to display along with the time AudioClip sound; // Sound to play when we reach 00:00 // Called when the applet is first loaded public void init() { // Figure out how long to count for by reading the "minutes" parameter // defined in a  tag inside the  tag. Convert to ms. String minutes = getParameter("minutes"); if (minutes != null) remaining = Integer.parseInt(minutes) * 60000; else remaining = 600000; // 10 minutes by default // Create a JLabel to display remaining time, and set some properties. label = new JLabel(); label.setHorizontalAlignment(SwingConstants.CENTER ); label.setOpaque(true); // So label draws the background color // Read some parameters for this JLabel object String font = getParameter("font"); String foreground = getParameter("foreground"); String background = getParameter("background"); String imageURL = getParameter("image"); // Set label properties based on those parameters if (font != null) label.setFont(Font.decode(font)); if (foreground != null) label.setForeground(Color.decode(foreground)); if (background != null) label.setBackground(Color.decode(background)); if (imageURL != null) { // Load the image, and save it so we can release it later image = getImage(getDocumentBase(), imageURL); // Now display the image in the JLabel. label.setIcon(new ImageIcon(image)); } // Now add the label to the applet. Like JFrame and JDialog, JApplet // has a content pane that you add children to getContentPane().add(label, BorderLayout.CENTER); // Get an optional AudioClip to play when the count expires String soundURL = getParameter("sound"); if (soundURL != null) sound=getAudioClip(getDocumentBase(), soundURL); // Obtain a NumberFormat object to convert number of minutes and // seconds to strings. Set it up to produce a leading 0 if necessary format = NumberFormat.getNumberInstance(); format.setMinimumIntegerDigits(2); // pad with 0 if necessary // Specify a MouseListener to handle mouse events in the applet. // Note that the applet implements this interface itself addMouseListener(this); // Create a timer to call the actionPerformed() method immediately, // and then every 1000 milliseconds. Note we don't start the timer yet. timer = new Timer(1000, this); timer.setInitialDelay(0); // First timer is immediate. } // Free up any resources we hold; called when the applet is done public void destroy() { if (image != null) image.flush(); } // The browser calls this to start the applet running // The resume() method is defined below. public void start() { resume(); } // Start displaying updates // The browser calls this to stop the applet. It may be restarted later. // The pause() method is defined below public void stop() { pause(); } // Stop displaying updates // Return information about the applet public String getAppletInfo() { return "Countdown applet Copyright (c) 2003 by David Flanagan"; } // Return information about the applet parameters public String[][] getParameterInfo() { return parameterInfo; } // This is the parameter information. One array of strings for each // parameter. The elements are parameter name, type, and description. static String[][] parameterInfo = { {"minutes", "number", "time, in minutes, to countdown from"}, {"font", "font", "optional font for the time display"}, {"foreground", "color", "optional foreground color for the time"}, {"background", "color", "optional background color"}, {"image", "image URL", "optional image to display next to countdown"}, {"sound", "sound URL", "optional sound to play when we reach 00:00"}, {"newpage", "document URL", "URL to load when timer expires"}, }; // Start or resume the countdown void resume() { // Restore the time we're counting down from and restart the timer. lastUpdate = System.currentTimeMillis(); timer.start(); // Start the timer } // Pause the countdown void pause() { // Subtract elapsed time from the remaining time and stop timing long now = System.currentTimeMillis(); remaining -= (now - lastUpdate); timer.stop(); // Stop the timer } // Update the displayed time. This method is called from actionPerformed() // which is itself invoked by the timer. void updateDisplay() { long now = System.currentTimeMillis(); // current time in ms long elapsed = now - lastUpdate; // ms elapsed since last update remaining -= elapsed; // adjust remaining time lastUpdate = now; // remember this update time // Convert remaining milliseconds to mm:ss format and display if (remaining < 0) remaining = 0; int minutes = (int)(remaining/60000); int seconds = (int)((remaining)/1000); label.setText(format.format(minutes) + ":" + format.format(seconds)); // If we've completed the countdown beep and display new page if (remaining == 0) { // Stop updating now. timer.stop(); // If we have an alarm sound clip, play it now. if (sound != null) sound.play(); // If there is a newpage URL specified, make the browser // load that page now. String newpage = getParameter("newpage"); if (newpage != null) { try { URL url = new URL(getDocumentBase(), newpage); getAppletContext().showDocument(url); } catch(MalformedURLException ex) { showStatus(ex.toString()); } } } } // This method implements the ActionListener interface. // It is invoked once a second by the Timer object // and updates the JLabel to display minutes and seconds remaining. public void actionPerformed(ActionEvent e) { updateDisplay(); } // The methods below implement the MouseListener interface. We use // two of them to pause the countdown when the mouse hovers over the timer. // Note that we also display a message in the statusline public void mouseEntered(MouseEvent e) { pause(); // pause countdown showStatus("Paused"); // display statusline message } public void mouseExited(MouseEvent e) { resume(); // resume countdown showStatus(""); // clear statusline } // These MouseListener methods are unused. public void mouseClicked(MouseEvent e) {} public void mousePressed(MouseEvent e) {} public void mouseReleased(MouseEvent e) {} }